As Fry, Mitchell is no Sigourney Weaver -- she's younger and blonder, and Ripley never carried herself like she had so much to prove. But she's smart and attractive enough to lead anyone's sci-fi/horror adventure, and Twohy's is a promising interpretation of the genre's enduring cliches.

From there, though, the story moves fairly slowly, never revisiting the energy of that white-knuckle opening reel. Crash-landed Mitchell and her crewmates, plus a few civilian survivors, are stranded in a long-deserted colony on a planet in the middle of galactic nowhere. Along for the ride was the strapping serial killer Riddick (big ol' Vin Diesel), a captive with whom the others must strike a deal -- his skills at piloting a small spacecraft off that desolate rock in exchange for his freedom.

The tension among this ensemble would be more believable if they weren't such stock characters -- the fussy Brit, the devout Muslim, the he-man crewman, etc. The only important relationship turns out to be the one between Fry and Riddick. Hhe's allowed to intimidate her without resort to crass remarks or misogyny. More than an imposing enigma, the muscular, intelligent Riddick is this film's hulking fetish object. His eyes even have a preternatural gleam to them, the product, he explains, of a covert laser operation to improve his night vision during a long, dark incarceration.

This makes him even more important to the other survivors, who soon learn they're sharing a planet with massive flocks of the ferocious nocturnal animals who did in the human population some two decades ago. The critters react to light like Count Dracula, and therefore stay hidden from the unremitting sunshine (the photographic techniques employed to convey the landscape beneath a trio of suns is gimmicky, but undeniably striking). But as sci-fi movie luck would have it, our heroes have visited on the eve of an alignment of planets that will cast a deep, dark shadow over their activities. One of the movie's coolest images shows the huge, ringed planet nearby moving across the sky and blotting out all light. And that's when the beasties come out to feed.

Since Jurassic Park, which heralded the arrival of computer-generated monster effects, the depiction of spooky, fleet-footed monsters has become commonplace in the multiplex. Under such circumstances, the aliens of Pitch Black manage to stand out from the pack. Apparently modelled loosely on pterodactyls, the winged and clawed animals are rarely on screen long enough for examination, but they do seem physical enough, a cross between the skeleton creatures of Ray Harryhausen and the polymorphous monsters of Ridley Scott and James Cameron.

What's more, they actually seem to share physical space with their human co-stars, which is still rare in the realm of cgi. A scene where Diesel, who has identified their blind spots, moves in an intricate sort of dance with one of them in order to keep from being seen, exudes athletic physicality. (Such gracefully choreographed attention to bodies and movement has long been a staple of Hong Kong action and has recently informed such Hollywood flicks as Blade and The Matrix.)

Every awesome visual or kinetic burst of action, however, is more than matched by a long section of expository tedium or tortured dialogue, and the genuinely high quality of the performances can't mask the general redundancy of everything that happens here. Pitch Black aspires to be nothing more than a visually spunky time-waster, and it does succeed at that. At its best, however, it suggests a level of craft that it can't maintain. There's lots of promise for this Twohy guy, assuming he gets hold of a more audacious story (maybe not his) next time around.